Re: The why and what for
Exactly my thinking, seems like Microsoft reinvented something well known in other ecosystems and very useful. That is : headless server platform optimized for running open source server software (e.g. open source version of .NET, ngix, Python etc.) on top of minimal kernel. Since large number of Windows shops do not understand the idea of "headless machine" they will obviously complain, but that does not make the whole idea wrong at all.
Is it something I could put to use personally? Probably not ... but I could toy with it, especially if it ran bare metal on cheap-and-cheerful ARM box. Or on top of kvm hypervisor on regular PC.